'use strict';
'use ndb';
{
    const org = 'HowProgrammingWorks';
    // delete org; // Raises SyntaxError in strict mode
}

{
    const country = {
        name: 'Chile',
        ruler: 'Augusto Pinochet',
        born: 1915,
        alive: false,
    };

    delete country.ruler;
    console.dir( { country } );

    delete country.born;
    delete country.population;
    console.dir( { country } );
}

{
    const o = { name: 'runs' };
    const bul_o = 'name' in o;
    debugger
}

{
    const currencies = [ 'BTC', 'EUR', 'UAH', 'USD' ];

    const ed = 1 in currencies;
    console.log( 'currencies[1]:', currencies[1], 1 in currencies );
    console.log( 'currencies[2]:', currencies[2], 2 in currencies );

    delete currencies[1];
    currencies[2] = undefined;
    console.dir( { currencies } );

    console.log( 'currencies[1]:', currencies[1], 1 in currencies );
    console.log( 'currencies[2]:', currencies[2], 2 in currencies );
}
